Sale 1:

https://backpack.tf/profiles/76561198047595874#!/compare/1548979200/1549152000

https://backpack.tf/profiles/76561198062781434#!/compare/1547683200/1549497600

SCM

https://steamcommunity.com/market/listings/440/Collector%27s%20Mad%20Milk

Sold for 20.60 CAD

Keys at 2.94 CAD

Total is ~7.00 keys

Sale 2:

https://backpack.tf/profiles/76561198073688836#!/compare/1545955200/1546473600

https://backpack.tf/profiles/76561198086972084#!/compare/1545523200/1546128000

Untrace

Sale 3:

https://backpack.tf/profiles/76561198086972084#!/compare/1546128000/1546214400

https://backpack.tf/profiles/76561198128550841#!/compare/1546041600/1546128000

Untrace

Sale 4:

https://backpack.tf/profiles/76561198090147535#!/compare/1547596800/1547683200

https://backpack.tf/profiles/76561198841707825#!/compare/1547596800/1547683200

Untrace

Sale 5:

https://backpack.tf/profiles/76561198841707825#!/compare/1547596800/1547683200

https://backpack.tf/profiles/76561198130503112#!/compare/1547596800/1547683200

Sold for ~5 keys

Sale 6:

https://backpack.tf/profiles/76561198130503112#!/compare/1549929600/1550016000

https://backpack.tf/profiles/76561198146569609#!/compare/1548979200/1550188800

Untrace

Sale 7:

https://backpack.tf/profiles/76561198128550841#!/compare/1546041600/1546128000

https://backpack.tf/profiles/76561198130503112#!/compare/1546041600/1546128000

Sold for ~4 keys

Sale 8:

https://backpack.tf/profiles/76561198130503112#!/compare/1547856000/1547942400

https://backpack.tf/profiles/76561198317416806#!/compare/1547942400/1548028800

Sold for ~5.53 keys

Sale 9:

https://backpack.tf/profiles/76561198317416806#!/compare/1548115200/1548201600

https://backpack.tf/profiles/76561198259733876#!/compare/1548115200/1548201600

QS

Sale 10:

https://backpack.tf/profiles/76561198259733876#!/compare/1550534400/1550620800

https://backpack.tf/profiles/76561198062581880#!/compare/1550448000/1550620800

Untrace

Sale 11:

https://backpack.tf/profiles/76561198335791307#!/compare/1549411200/1549497600

https://backpack.tf/profiles/76561198121860801#!/compare/1549238400/1549497600

Sold for 7 keys

Sale 12:

https://backpack.tf/profiles/76561198121860801#!/compare/1549497600/1549756800

https://backpack.tf/profiles/76561198195404813#!/compare/1549497600/1549584000

https://backpack.tf/profiles/76561198896699737#!/compare/1550361600/1550448000

https://backpack.tf/profiles/76561198462815806#!/compare/1550448000/1550534400

Untrace

Marketplace.tf:

https://marketplace.tf/items/222;14

2 buy orders,

$14.98 / $1.81 = 8.28 keys

Bot.tf Sales:

https://bot.tf/stats/item?def=222&q=14&ef=&craft=1&aus=0&ks=0

Past Month

7 keys (x2)

Bought:

5.23(x1)

Total sales @:

4, 5, 5.23, 5.53, 7, 7, 7, 7, 8.28 keys

Buyers up to 5.57 keys,

Let's take 7 flat, considering that 8.28 is a outlier.